The electrical circuit system is the "power core" of cold storage units. Whether the wire selection and grounding resistance meet the standards directly determines the safe operation and service life of the equipment. Many cold storages have electrical circuit hidden dangers, such as undersized wire selection and excessive grounding resistance (>4Ω). Although these seem to be omissions in construction details, they will actually cause faults such as overload tripping and contactor burnout, and also hide risks of electric leakage and electrical control system failure. The subsequent losses far exceed the cost saved in the early stage.

The risk of undersized wire selection stems from the starting characteristics of the unit. The starting current of cold storage units can reach 3-5 times the rated current, which requires the wires to have sufficient carrying capacity. If undersized wires are selected, they cannot withstand the current impact during startup, leading to line overload and heating. This not only easily triggers overload protection tripping, but also accelerates the aging and burnout of contactor contacts. As a key component of circuit control, the damage of the contactor will directly cause the unit to shut down. At the same time, high temperature may also cause the aging of the line insulation layer, laying hidden short-circuit dangers.

The hidden danger of excessive grounding resistance (>4Ω) is more dangerous. The grounding system is the "safety barrier" of the cold storage, and its core function is to quickly conduct the current generated by equipment leakage or lightning into the ground. When the resistance exceeds the standard, the leakage current cannot be discharged in time, which will cause the unit shell to be electrified, threatening the personal safety of operators. At the same time, it will also interfere with the signals of the electrical control system, causing faults such as sensor failure and incorrect startup/shutdown of the unit. In severe cases, it may even burn out the control main board and lead to equipment paralysis.

Electrical circuit construction must strictly follow double standards: wire selection must match the starting current of the unit, and national standard copper core wires should be selected in accordance with regulations to eliminate the replacement of undersized wires; the grounding system must use qualified grounding electrodes, and professional instruments should be used for testing after construction to ensure that the grounding resistance is ≤4Ω. Before commissioning, it is also necessary to fully check the line insulation and contact conditions, and rectify hidden dangers in a timely manner to avoid operation with faults.

There is no room for luck in cold storage electrical circuit safety. Qualified wire selection and grounding resistance are the bottom-line requirements. Investing in standardized construction and testing in the early stage may seem to increase initial expenses, but it can effectively avoid shutdown losses, maintenance costs and safety risks. Paying attention to the investigation of hidden dangers in the electrical circuit system is the only way to build a solid "power defense line" for the stable operation of cold storage units.